How to Easily Replace the Glass in Your UPVC Windows Step by Step Guide

Replacing the glass in your UPVC windows might seem like a daunting task, but with the right approach and tools, it can be a straightforward DIY project. Whether your window glass is cracked, broken, or just old and foggy, changing it yourself can save you money and give you a sense of accomplishment. This guide walks you through the entire process, breaking it down into clear, manageable steps.

Step-by-step replacement of glass in a UPVC window frame

Understanding UPVC Windows and Their Glass

UPVC (unplasticized polyvinyl chloride) windows are popular for their durability, low maintenance, and energy efficiency. The glass used in these windows is usually double-glazed, meaning two panes of glass are sealed together with a spacer in between. This design improves insulation but also means replacing the glass requires care to maintain the seal and fit.

Before starting, it’s important to identify the type of glass unit you have. Most UPVC windows use sealed double-glazed units (DGUs), but some older models might have single panes or different configurations. Knowing this helps you order the correct replacement glass.

Tools and Materials You Will Need

Gathering the right tools before you begin will make the process smoother. Here’s a list of essentials:

• Replacement glass unit (double-glazed or single pane as needed)

• Glazing beads (plastic strips that hold the glass in place)

• Glazier’s points or clips (if applicable)

• Putty knife or flat screwdriver

• Utility knife

• Gloves and safety glasses

• Tape measure

• Silicone sealant or glazing compound

• Hammer and small nails (optional)

• Suction cups for handling glass (optional but helpful)

  
  

Having these ready will help you avoid interruptions during the replacement.

Step 1: Remove the Window Sashes or Panels

Most UPVC windows have removable sashes or panels that hold the glass. Start by opening the window fully and locating the screws or clips that secure the sash to the frame. Carefully remove these fasteners and gently lift out the sash. If your window does not have removable sashes, you may need to work directly on the frame.

Handle the sash carefully to avoid damaging the UPVC frame or the remaining glass.

Step 2: Remove the Glazing Beads

Glazing beads are the plastic strips that hold the glass in place within the sash or frame. Use a putty knife or flat screwdriver to gently pry the beads away. Work slowly to avoid cracking or breaking them, as you may be able to reuse them.

If the beads are brittle or damaged, it’s best to replace them with new ones to ensure a secure fit for the new glass.

Step 3: Take Out the Broken or Old Glass

Once the glazing beads are removed, the glass should be loose. Put on gloves and safety glasses before handling the glass to protect yourself from sharp edges.

Carefully lift the glass out of the frame. If it’s broken, remove all shards and clean the frame thoroughly. Use a vacuum or brush to clear any debris or old sealant.

Step 4: Measure the Opening Accurately

Accurate measurements are crucial for ordering the right replacement glass. Measure the width and height of the glass opening inside the frame, not the glass itself. Take measurements at several points to account for any irregularities.

Subtract a few millimeters (usually 3-5 mm) from each dimension to allow for expansion and fitting clearance. Write down these measurements clearly.

Step 5: Order the Replacement Glass

With your measurements in hand, order the replacement glass unit from a reputable supplier. Specify the type of glass (double-glazed or single pane), thickness, and any special features like low-emissivity coating or toughened glass.

Delivery times vary, so plan accordingly. Some suppliers offer custom cutting and sealing services, which can simplify installation.

Step 6: Prepare the Frame for New Glass

Before installing the new glass, clean the frame thoroughly. Remove any old sealant or putty using a utility knife or scraper. Wipe down the surface to ensure it’s dry and free of dust.

If the glazing beads were damaged, replace them now. Check that the frame is in good condition and repair any cracks or damage.

Step 7: Install the New Glass Unit

Place the new glass carefully into the frame or sash. Use suction cups if available to handle the glass safely and avoid fingerprints or smudges.

Press the glass firmly but gently into place, ensuring it sits evenly on the frame. If your window uses glazing clips or points, secure the glass with them now.

Step 8: Reattach the Glazing Beads

Snap or press the glazing beads back into place around the glass. Make sure they fit snugly and hold the glass securely without gaps.

If the beads don’t fit well, use a small amount of silicone sealant to fill any spaces and improve the seal.

Step 9: Seal the Edges

Apply a thin bead of silicone sealant around the edges of the glass where it meets the frame. This prevents drafts and moisture from entering.

Smooth the sealant with a finger or a sealant tool for a clean finish. Allow it to cure according to the manufacturer’s instructions.

Step 10: Reinstall the Window Sashes or Panels

Once the sealant is dry, put the sash or panel back into the window frame. Secure it with screws or clips removed earlier.

Test the window to ensure it opens and closes smoothly and that the glass feels stable.

Tips for a Successful Glass Replacement

• Work on a flat, stable surface to avoid accidents.

• Always wear protective gloves and glasses.

• If the glass is large or heavy, ask for help to avoid injury.

• Keep children and pets away from the work area.

• Dispose of broken glass safely in a sturdy container.

• Take photos during disassembly to help with reassembly.

• If unsure about any step, consult a professional glazier.

  
  

Replacing the glass in your UPVC windows is a manageable task with patience and care. By following these steps, you can restore your windows’ appearance and insulation without the cost of professional help. If you encounter unexpected issues or damage to the frame, don’t hesitate to seek expert advice.

Your next step is to gather your tools and order the right replacement glass. With preparation and attention to detail, your UPVC windows will look and perform like new again.